homemade converts - what frame mods

I am going to be taking the roof of my car due to excessive rust (and either converting to a folding top or another roof) but for the summer I may go topless. I know the factory frame is not strong enough to keep the car supported without a roof.

For those that have cut your roofs off or converted to a folding top what frame mods have you done to keep your car from folding up/ bending.. (i.e. allowing the doors to still shut). I want to keep it ridged.

are you adding X or K members or other frame support structures. any pictures would be great.

 

What kind of car?

 

besides the frame, dont you think you might need to do something about the body like bracing between front floor brace and rear floor brace?

 

sorry, 49-54 chevy.. mine is a 51... 2 dr hardtop. It has some extra bracing from the factory in the frame compared to sedans but not enough to support no top.

at this time, I am just looking at options in case I go this way.

 

No problem whack away......

 

I thought the convertible and the hardtops had the same frame? If so it should be able to support it, but your B Pillar area will be all kinds of soggy!!!

 

Being a hardtop the body should be beefed up a bit from factory at the "b" pillar area. Having no roof from factory converts still move around a bit. You could box your frame and put some more supports in the body to stiffen it up.....make your uspension work well and travel making it do all the twisting

 

If the frames are the same, I'd mostly be concerned with the rocker boxes. That's where a lot of factory convertibles differ from hardtop and sedan shells. Cutting off the outer rocker and putting a big beefy reinforcement on the inner rocker to tie the body mounts and cowl together, then putting the rocker back on over the top would reduce the tendancy of the doors to pinch, which is probably the biggest problem topless cars have.

A 49-52 Chevy or Pontiac convertible top rack is supposed to be a fairly straightforward swap onto the hardtop shell, but those cars could pull off the Carson top look too with the right mods.

 

'49-'54 Chevys have a hat section frame, with a flat piece rivetted on the open bottom of the hat. Ragtops have an extra piece of flat added on.
Other than that, the frames are all the same.

 

I had a problem car, I did for a guy...56 Ford ragtop. The body was pretty rotted, repaired once, but it had the usual weak supprt problems on an old convert.
When I did the bodywork, I inserted a 2 x 2, 1/8 wall tube, full length in the rocker box. Spot welded to the sill plate area, and the inner rocker. Ran as far as possible front and rear.

I also ran a 1 x 1 1/2 up each door jamb, welded to the 2x2, and a 1x1 from almost the top, to the end of the 2x2, at the rear wheelwell. I also did a 1x1 1/2 under the backseat, welded to the factory brace, and the floor. This stiffened up the body immensely, and the owner never had any problems opening the doors on an incline, or even on my lift! The dash stifffens up the front enough so no extra bracing is needed
The Fords also used solid body mounts, instead fo rubber, to help stiffen up things, you might want to do that, as well.
Later (55-7) Chevies used an X frame under the converts that the hardtop did not have. They also had a 1/4" thick steel plate running uner the regular frame for extra stiffness.
You can't stiffen up a convert enough!

 

The hard top has the same chassis as the vert. Your body should also already be braced proprerly.

 

These are all good points and as I have seen some open air roadsters take little time at all to complete

 

Ken,the 1935 - 40 Fords had extra reinforcement in the front of the member section going out to the frame rails where the cowl would be bolted in place.

HRP

 

I have a 49 chevy convert thats rusty and a 51 hardtop that I'm going to combine to build into a convert. The convert frame has a really large x- member, frame thickness is slightly more and has some much stronger bracing at the bottom of the B pillar at the rockers/floor for support. I'll see if I can get a pic of the x-member section for you.

 

Thanks Tbird, would like to see pictures


I know the hardtop frame has an extra piece of metal welding inside the tophat portion (like the convert) but it does not have the extra X member referenced above. I know i could duplicate but thought I would see what others have done. I am not aware of the factory converts having any extra bracing in the rockers but possibly by the B piller?

 

These are some pics of the convert frame. The X member is massive and adds a lot of support to the body between the A pillar and B pillar.

 

thanks tbird for the shots. that looks like one rusty remains of a convert but your shots allow me to see the size and mass of the factory set up

I have decided I will be going topless with mine. I have purchased a complete folding top assembly and top half of the windshield frame. I will use some pieces from Art Morrison Chassis to build my new frame re-inforcement

 

that is not a 49 chevy frame is it ? i thought they were hat type...

 

The frame is the top hat style on the 49 chevy but the X member that GM installed on the converts are I-beam.

 

Chopolds has a good point. Don't forget to reinforce the body especially in the rocker panel or sills, door post, and cowl area. This may be more important than the frame although both are important.

You should brace up the body before you cut the top off.

If you got the top off an old convert could you inspect what was left of the body and see how the factory reinforced it?

 

If the frame is in decent shape, cutting the top off ain't gonna make it fold up. After all, you're actually lightening the car. But the body will totally "go away" without lots of bracing. Brace, brace, more brace ... paying special attention to the A-pillars; they're gonna have to support the weight of the doors -- without the help of a rigid roof.

 

If anybody has a 49-52 Dodge Wayfarer Business Coupe they want to turn into a factory convert, check my ad in the classifieds. I have the cowl, doors and rear section, plus the X-member for the frame, along with the complete top mechanism. Turn your bizzy coupe into a gennie convert - a single seat little hot rod. Just add a small hemi and you'll be the hit of the cruise.